Method for determining diagenetic process and porosity evolution process of foreland basin sandstone reservoir

Abstract

The invention provides a method for determining a diagenetic process and a porosity evolution process of a foreland basin sandstone reservoir. The method comprises steps as follows: determining reservoir genesis and petrologic features; determining a burial process and tectonic uplift and subsidence periods; determining a diagenesis type, features and strength of the reservoir by a cathodoluminescence microscope and / or through QEMScan (Quantitative Evaluation of Minerals by SCANning electron microscopy), and recovering the diagenetic process; determining reservoir space features and the porosity evolution process by a fluorescence microscope and / or a confocal laser scanning microscope. With the adoption of the method, the diagenetic process and the porosity evolution process of the ultra-deep compact foreland basin sandstone reservoir with complicated burial process, extremely great depth, extremely small pores and extremely low porosity and permeability can be effectively analyzed; the method can be used for predicating the quality of the sandstone reservoirs in different areas in the plane and the vertical profile, so that more and larger oil and gas fields can be discovered.

Description

technical field [0001] The invention relates to a method for determining the diagenesis process and pore evolution process of a sandstone reservoir in a foreland basin, and belongs to the technical field of petroleum exploitation. Background technique [0002] Foreland basins are an important place for the enrichment of oil and natural gas. At present, there are many evaluation techniques for the diagenesis and pore evolution process of sandstone reservoirs in foreland basins at home and abroad. A large number of studies have been carried out on the Sandstone reservoirs with low porosity, medium and low permeability in the Triassic and Triassic, and the Paleogene-Neogene low-porosity and low-permeability sandstone reservoirs in the northwestern margin of the Qaidam Basin. However, the deposition and burial processes of the sandstone reservoirs in these foreland basins are relatively simple, the pores are relatively developed, and the physical properties are relatively good....

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Problems solved by technology

[0006] However, conventional cast thin sections are mainly researched on micron-scale and above pores, while for tight sandstone with very small pores and extremely low porosity and permeability, the pore diameter is generally on the order of several microns to several nanometers. After the colored epoxy resin is injected into the nano-scale pores , due to its very small amount, it is difficult to identify the pores even under a high-power microscope

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